1. Field of the Invention
The present invention relates to a technical field for inspecting a printed circuit board (hereafter referred to as “component mounting substrate” or simply referred to as “substrate”) with components mounted. Particularly, the present invention relates to an apparatus having a function for executing an inspecting method to be executed between a first component mounting step and a second component mounting step in a fabricating line in which mounting a component is executed in two separate stages and a function for executing the inspecting method.
2. Description of the Prior Art
A component mounting machine referred to as “mounter” has been used so far in order to automate high-density component mounting. Conventional mounters include a mounter (generally referred to as “high-speed mounter”) having a function for mounting a small component such as a chip component at a high speed and a mounter (generally referred to as “odd-shape mounter”) for mounting odd-shaped components such as BGA, CSP, and IC.
In the case of a conventional general substrate fabricating line, processing of printing cream solder on a bare substrate is first performed in a solder printing machine and then the substrate is sent to a high-speed mounter and an odd-shape mounter in order to mount the above various components. Moreover, the substrate after mounting components is sent to a reflow furnace to undergo soldering.
A substrate inspecting apparatus is properly set to the rear stage of each mounter. The substrate inspecting apparatus inspects a cream-solder printed state on a substrate and whether components are correctly mounted on component mounting positions and only substrates passing the inspection are sent to the reflow furnace.
For example, a technique is disclosed in Japanese Patent Laid-Open Publication No. 2002-183712 as a prior art showing this type of inspection. In Japanese Patent Laid-Open Publication No. 2002-183712, an image of a character string printed on the main portion of a component is extracted from an image obtained by imaging a substrate to be inspected to recognize the characters and thereby it is determined whether a correct component is mounted.
The high-speed mounter repeatedly executes processing of attracting a component supplied from a component supplying device by an attracting nozzle, processing of carrying the attracted component up to a component mounting position, and processing of releasing the attracted component at the component mounting position. A component may be flown to a position different from the original mounting position (this phenomenon is hereafter referred to as “component fly”).
A component is flown due to various factors. It is considered as the most possible factor that a component is attracted in an unstable state due to abrasion of an attracting nozzle and dropped before it reaches a mounting position. Moreover, two components are simultaneously attracted by an attracting nozzle and one of them may be dropped to a position different from the original mounting position or while the attracting nozzle carries a component or when mounting the component, the component may contact with other component and the other component may fly to other position.
Furthermore, component fly may occur also when an air pressure or attraction time for attracting a component is incorrectly set and thereby the timing for canceling the attraction of the component becomes incorrect or a component size is not fitted to the diameter of a nozzle because an incorrect component is supplied to a component supplying device.
Furthermore, when cream solder falls short because a mask clogs or a squeezee is abraded, the adhesive strength of the solder decreases. Therefore, when a component is carried to the next step after mounted, the component may fly due to the force of carrying the component.
Thus, when component fly occurs in a high-speed mounter, the flown component drops to a mounting position of the odd-shaped component, and under this state, a substrate is sent to a odd-shape mounter, the odd-shaped component is mounted on the flown component and thereby, a trouble may occur.